The invention relates generally to data storage systems that can be used in computer systems and computer networks. More particularly, the invention relates to assigning signals to the contacts of a connector for usage with different types of disk drives in the data storage systems.
Referring to FIG. 1, a typical storage system 10 includes at least one rack 12 of storage devices or enclosures 14, 14xe2x80x2. The storage system 10 can have fewer or more enclosures than those shown (internal or external to the rack 12). In general, the enclosure 14 is a storage device having a plurality of disk modules 18. Examples of storage devices include disk-array enclosures (DAE) and disk-array processor enclosures (DPE). A typical DAE includes a plurality of disk modules (e.g., fifteen), one or two link control cards (LCCs), and one or two power supplies. A typical DPE includes a plurality of disk modules (e.g., fifteen), one or two storage processors, one or two LCCs, and one or two power supplies. Disk modules 18 include a carrier assembly that holds a disk drive and slides into the enclosure 14.
Each enclosure 14, 14xe2x80x2 implements redundancy with an xe2x80x9cAxe2x80x9d side and a xe2x80x9cBxe2x80x9d side. In enclosure 14, for example, each side has a link control card (LCC) 22, 22xe2x80x2 and a power supply (not shown). Reference numerals for the B side components are the same as corresponding components on the A side with the addition of a prime (xe2x80x2) designation. Each LCC 22, 22xe2x80x2 includes a primary communications port 26, 26xe2x80x2 and an expansion communications port 30, 30xe2x80x2. The enclosures 14, 14xe2x80x2 are connected to each other by cables 34, 34xe2x80x2 in a loop topology. Communication signals traverse the loop in one direction and pass from enclosure 14 to enclosure 14xe2x80x2, in a daisy-chain fashion, and then return from enclosure 14xe2x80x2 to enclosure 14. An enclosure receiving communication signals targeted for a different enclosure forwards those signals along the loop.
A common implementation of the loop is a Fibre Channel arbitrated loop. Fibre Channel is a computer communications protocol for communicating signals at a data rate of up to 2 Gbps. In general, the Fibre Channel protocol provides an interface by which host processors (and servers) communicate with the enclosures 14 and with the disk modules 18 installed within the enclosures 14. Typically, the disk modules 18 have Fibre Channel disk drives.
Disk drive manufacturers have for many years produced another type of disk drive, called Advanced Technology Attachment (ATA) disk drives, for the personal computer (PC) industry. To satisfy the high volumes and the small profit margins of PCs, the disk drive manufacturers have refined their processes to improve the reliability and storage capacity of the ATA disk drives and to reduce their cost. Typically, the cost of an ATA disk drive is two to three times lower and its storage capacity two times greater than that of a Fibre Channel disk drive. Thus, the net price per storage capacity advantage for ATA disk drives can be four to six times that of Fibre Channel disk drives. Consequently, ATA disk drives present an attractive adjunct to Fibre Channel disk drives for storage system developers and have found their way into storage systems. The price and capacity benefits gained from ATA disk drives come, however, at a loss of performance. Fibre Channel disk drives generally perform at twice the speed of ATA disk drives.
This tradeoff is likely to lead to the mixing of Fibre Channel and ATA disk drive types within a storage system. A problem occurs, however, when an ATA disk drive is mistakenly installed in a Fibre Channel enclosure. ATA disk drives are incompatible with Fibre Channel LCCs because they communicate according to different protocols. Thus, an ATA disk drive in a Fibre Channel enclosure is an inoperative combination. Further, the incorrect installation can cause damage to the ATA disk drive, to the Fibre Channel enclosure or to both, and can also cause the entire Fibre Channel arbitration loop, and thus the storage system, to fail. Therefore, there is a need to provide a mechanism that mitigates the effects of the improper installation of an ATA disk drive in a Fibre Channel enclosure.
In one aspect, the invention features a method for adapting to an incompatible disk drive that has been installed in a storage enclosure. A first signal is received at a disk module from a control board indicating a type of the control board. In response to the first signal, it is determined that the type of the control board is incompatible with a disk drive that is installed in the storage enclosure. A second signal is sent from the disk module to the control board that causes the control board to bypass the installed disk drive.
In another aspect, the invention features an adapter board for providing an interface between a disk drive and a control board. The adapter board comprises an electrical connector having a contact for providing an electrical interface to a signal line when the adapter board is in electrical communication with the control board. The adapter board also includes a controller, electrically connected to the contact of the electrical connector, for sending a signal through the contact to the control board by way of the signal line when the adapter board is in electrical communication with the control board. The signal has a first function when a type of the control board is incompatible with the disk drive and a second function when the type of control board is compatible with the disk drive.
The invention also features a disk module comprising a disk drive and an adapter board. The adapter board is electrically connected to the disk drive for providing an interface between the disk drive and a control board. The adapter board includes an electrical connector having a contact for providing an electrical interface to a signal line when the adapter board is in electrical communication with the control board, and a controller electrically connected to the contact of the electrical connector for sending a signal through the contact to the control board by way of the signal line when the adapter board is in electrical communication with the control board. The signal having a first function when a type of the control board is incompatible with the disk drive and a second function when the type of control board is compatible with the disk drive.
The invention also features an enclosure of a storage system, comprising a disk module having a disk drive and an adapter board electrically connected to the disk drive for providing an interface between the disk drive and a control board. The adapter board includes an electrical connector having a contact for providing an electrical interface to a signal line when the adapter board is in electrical communication with the control board, and a controller electrically connected to the contact of the electrical connector for sending a signal through the contact to the control board by way of the signal line when the adapter board is in electrical communication with the control board. The signal has a first function when a type of the control board is incompatible with the disk drive and a second function when the type of control board is compatible with the disk drive.
In still another aspect, the invention features a disk module, comprising a disk drive communicating according to a first protocol, and an adapter board electrically connected to the disk drive and configured to electrically communicate with a first type of control board that communicates according to the first protocol and with the disk drive. The adapter board has a capability of communicating with a second type of control board that uses a second protocol to communicate with disk drives. The second protocol is incompatible for communicating with the disk drive.
Also, the invention features an adapter board for providing an interface between a disk drive and a control board. The adapter board comprises electrical contact means for providing an electrical interface to a signal line when the adapter board is in electrical communication with the control board, and means for sending a signal through the electrical contact means to the control board by way of the signal line when the adapter board is in electrical communication with the control board. The signal has a first function when a type of the control board is incompatible with the disk drive and a second function when the type of control board is compatible with the disk drive.